1. Field of the Invention
The present invention relates generally to infusion or transfusion systems, and more particularly to an injector utilized therein.
2. Description of the Prior Art
The injector disclosed in U.S. Ser. No. 550,086, filed Nov, 9, 1983, assigned to the present assignee, comprises a cylindrical housing containing a duct. The outlet of the duct is configured for insertion into a nipple on a transfer tube. The inlet of the duct is covered by a membrane. The membrane can be penetrated by a cannula of a syringe in order to injecet a substance into the duct of the housing. A thick, porous material is disposed within the duct between the outlet and the inlet, to filter out solid particles that may contaminate the injected substance. The end of the housing proximate the membrane extends over the membrane, forming a cap which securely positions the membrane against the inlet of the duct. A hole is disposed in the cap through which a cannula may be inserted into the membrane. The edge of the cap surrounding the hole is turned inward, toward the membrane, pressing the membrane against a shoulder of the housing proximate the inlet of the duct. Owing to the elasticity of the membrane, its central portion protrudes somewhat, forming a convex surface covering the inside of the hole. Accordingly, a recess is created where the periphery of this convex surface meets the edge of the cap bounding the hole.
Disinfection of the membrane around a cannula puncture point is difficult, since germs may invade the recess, where they settle and are substantially protected from sterilization. Also, moisture may accumulate in the recess, affording a fostering culture medium or such germs. The puncture region of the membrane, being arched, jeopardizes disinfection.
Thus, there is a need for an injector having a membrane whose puncture zone is easy to keep clean and to disinfect.